How to Block Your Number When Making a Call

Blocking your number before a call — so the recipient sees "Unknown," "Private," or "No Caller ID" instead of your digits — is a built-in feature on virtually every phone platform. It doesn't require a special app, a paid service, or technical expertise. But the exact method, and how reliably it works, varies depending on your device, carrier, and who you're calling.

What "Blocking Your Number" Actually Does

When you block your number, you're activating caller ID suppression — technically known as sending a CLIR (Calling Line Identification Restriction) request. Your phone tells the network not to pass your number to the recipient's caller ID system.

This doesn't make you anonymous to your carrier. Your carrier always knows which number initiated the call. CLIR only affects what displays on the receiving end.

The Two Main Methods 📱

1. Per-Call Blocking with a Prefix Code

The fastest method — no settings to change, works call by call.

In the US and Canada, dial *67 before the number:

*67 + 1 + area code + number 

Example: *671234567890

The call goes through normally. Your number shows as "Private" or "No Caller ID" on the other end. This resets after every call — your number shows normally on your next unmodified call.

Other regions use different codes:

If you're outside these regions, a quick search for "caller ID block code [your country]" will surface the correct prefix.

2. Permanent Blocking Through Phone Settings

If you want your number hidden on every outgoing call by default, you can set this at the OS level.

On iPhone (iOS):

• Go to Settings → Phone → Show My Caller ID
• Toggle it off

Your number will be hidden on all calls until you re-enable it.

On Android:

• Go to Phone app → Settings (three dots or gear icon) → Calls → Additional Settings → Caller ID
• Select "Hide number"

The exact path varies slightly by Android version and manufacturer (Samsung, Pixel, OnePlus all have slightly different menu structures), but the option is consistently found within the Phone app's call settings.

Carrier-Level Blocking

Some carriers offer account-level caller ID blocking — a setting applied to your line that suppresses your number across all calls. This is useful if you're using a basic handset with limited settings menus, or if you want the block applied regardless of which device you use with your SIM.

Contact your carrier directly to enable or disable this. It's typically free, though some carriers apply restrictions on business accounts or prepaid plans.

Important Limitations to Understand 🔍

Blocking doesn't always work the way you expect:

• Toll-free numbers (800, 888, 877, etc.) often ignore caller ID suppression. Companies using toll-free lines frequently subscribe to ANI (Automatic Number Identification) services, which deliver your number through a separate system that bypasses CLIR entirely.
• Emergency services (911 in the US) always receive your number regardless of any blocking settings. This is a legal requirement.
• Some recipients block calls from hidden numbers entirely. Many people and businesses use call-screening services that automatically reject or send to voicemail any call showing as "Unknown" or "Private."
• VoIP services (like Google Voice, WhatsApp calls, or Skype) handle caller ID differently. *67 typically doesn't apply to VoIP-to-VoIP calls, and the behavior varies by platform.

Unblocking a Blocked Number Temporarily

If your number is permanently blocked (via settings or carrier), you can reveal it for a single call by dialing *82 before the number in the US. This temporarily overrides the block for that one call — useful if you're calling a number that screens or rejects private calls.

When the Method That Works for You Depends on Your Situation

The right approach shifts depending on a few variables:

• How often you need to block — occasional use favors *67; frequent use favors the settings toggle
• Your platform — iOS and Android differ in where the setting lives and how consistently it applies
• Your carrier — some carriers have quirks with permanent blocking, especially on MVNOs or prepaid plans
• Who you're calling — calling businesses, toll-free lines, or VoIP services introduces variables that no single method fully controls

The mechanics are straightforward. What determines whether your block works as intended — and which method fits your habits — comes down to the specific combination of your device, your carrier, and the nature of the calls you're making.